Time evolution of the exponential wavenumber spectra of turbulence upon helium injection into a hydrogen discharge at the FT-2 tokamak
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The effect of variations in the key parameter of short-wavelength turbulence—the ion-acoustic Larmor radius ρ s , which determines the position of the maximum of the drift instability growth rate over poloidal wavenumbers—was studied experimentally at the FT-2 tokamak. For this purpose, helium was injected to hydrogen plasma, which resulted in a change in the electron temperature at the plasma edge. The universality of the exponential shape of the turbulence spectra over radial wavenumbers q and a substantial excess of the characteristic turbulence scale L over the ion-acoustic Larmor radius was confirmed with the help of correlative diagnostics of enhanced scattering. This excess at the discharge periphery reaches a value of 3–5 at a low electron temperature, apparently, due to an increase in the dissipation of drift waves upon their cascade transfer toward short scale-lengths.
KeywordsPlasma Physic Report Plasma Edge Turbulence Spectrum Drift Wave Wavenumber Spectrum
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- 9.A. D. Gurchenko, E. Z. Gusakov, S. I. Lashkul, et al., Proceedings of the 38th EPS Conference on Controlled Fusion and Plasma Physics, Strasbourg, 2011, ECA 35G, P2.128 (2011).Google Scholar
- 12.G. V. Pereverzev and P. N. Yushmanov, Preprint No. 5/98 (Max Planck Inst. for Plasma Physics, Garching, 2002).Google Scholar
- 18.J. Weiland, Collective Modes in Inhomogeneous Plasmas: Kinetic and Advanced Fluid Theory (IOP, London, 2000).Google Scholar